As mentioned above, a TiO2 thin film may be formed on a substrate for various purposes, and a method of forming a TiO2 thin film on a substrate by an atmospheric pressure CVD method has been proposed.
In the case where a TiO2 thin film is formed as a layer constituting a part of an antireflection film, a silicone oxide (SiO2) thin film as a low refractive index film having a refractive index lower than that of TiO2 and the TiO2 thin film are alternately laminated. Here, in the case where the SiO2 thin film and the TiO2 thin film are formed by using the atmospheric pressure CVD method, the deposition rates of these thin films are desired to be high from the viewpoint of an improvement in productivity.
Also in the aforementioned other use applications, the deposition rate at the time of TiO2 thin film formation by the atmospheric pressure CVD method is desired to be high from the viewpoint of an improvement in productivity.
Furthermore, for example, Patent Document 1 discloses a method for forming a thin film of tin-containing titanium oxide, which exhibits a photocatalytic activity, mainly by a CVD method in a float bath while adding highly reactive titanium chloride as a main raw material and an ester or the like as an oxygen source.